Ages and stable isotopes along cores of moss collected from various coastal ice-free sites around Antarctica

Full description

This record contains carbon-14 (radiocarbon) and carbon-13 (stable carbon isotope) data associated with cores of moss sampled between 2004 and 2018, under projects ASAC_1313, AAS_2542, AAS_3042, AAS_3129, AAS_4046, AAS_4516 and AAS_4613. This record provides information about sample collection details, carbon-14 ages and stable carbon-13 isotope values along cores of moss collected from various coastal ice-free sites around Antarctica.

This record was prepared by Melinda Waterman in December 2024.

Ages, growth rates and stable carbon (δ13C) isotopic signatures of 34 moss shoots/cores collected from five locations around coastal Antarctica.

Samples of five moss species were analysed; Bryoerythrophyllum recurvirostre, Bryum pseudotriquetrum, Ceratodon purpureus, Chorisodontium aciphyllum and Schistidium antarctici. Carbon-14 and carbon-13 (δ13C-graphite) were measured in over 400 moss segments using mass spectrometry techniques. δ13C-graphite was corrected for fluctuations in atmospheric δ13C, reflected as Δ13C. δ13C (or Δ13C) reflects moss water availability during growth (Bramley-Alves et al. 2015).

FILE: AAS_4516_MossAges.xlsx This Excel file contains three worksheets:

1. "Sheet 1: Information" – provides a detailed description of methods, terms and abbreviations.
2. "Sheet 2: Sample collection" – provides information about sampling collection details
3. "Sheet 3: Moss core 14C and d13C" – provides carbon-14 ages and stable carbon-13 isotope values

Key to column headings in “Sheet 2: Sample Collection”

Location = Region within East Antarctica or Maritime Antarctica where samples were collected. Samples have been collected from either the Windmill Islands, Vestfold Hills, Ross Sea Region and the McMurdo Dry Valleys, and Dronning Maud Land (East Antarctica), South Shetland Islands (Maritime Antarctica)

Sample code in Waterman et al. (in prep) = Label code given to individual cores published in Waterman et al. (in prep - to be included here when published). These are coded in order of Species, Location/Site, Sample Number. e.g. BP A135 S1 = Bryum pseudotriquetrum ASPA135 Sample #1

Species = Bryoerythrophyllum recurvirostre (BR), Bryum pseudotriquetrum (BP), Ceratodon purpureus (CP), Chorisodontium aciphyllum (CA), Schistidium antarctici (SA)

Peninsula = Names of specific peninsula, island or harbour where ice-free areas samples were collected from within "location". For abbreviation of sites not located on a peninsula: Is = Island, Hbr = Harbour, R. Ridge = Robinson Ridge

Site = Name of Antarctic Specially Protected Area (ASPA), locality or site where samples were collected from within "Peninsula". Some samples collected within ASPAs 135 and 136 have been grouped according to relative proximity to each other: (a) and (b) refer to two groups within ASPA 135 on Bailey Peninsula, and SC and CR refer to Stevenson's Cove and Clark Ridge within ASPA 136 on Clark Peninsula.

Sample number = Number/ID of sample collected and analysed as part of this data record, e.g. 1, 2 or 3.

Date collected of specific samples in DD/MM/YYYY format

Latitude and Longitude in DDD° MM' SS.S" (decimal seconds where applicable)

Total length (mm) of collected core after rehydration in MilliQ water and subsampling in preparation for carbon-14 dating.

Depth analysed (mm) = the maximum depth in millimetres of moss core segment that was analysed using radiocarbon or stable isotope analysis for each individual core sample.

See Sheet 3 for results of each analysed segment.
Key to column headings in "Sheet 3: Moss core 14C and d13C":

Location = region (e.g. Windmill Islands, South Shetland Islands) where the moss core samples was collected from

Peninsula/island = Peninsula or Island within region as specified above

Site = locality within peninsula or island, and the Antarctic Specially Protected Area number if relevant

Species = species of moss collected. Each core is of a clump of individual plants of one species only

Sample code upon collection = label when core was collected Sample code in Fig. 2 and 3 in Clarke et al. (2012) = how sample was referred to in Clarke et al. (2012) Sample code in Fig. 7 in Bramley-Alves et al. (2015) = how sample was referred to in Bramley-Alves et al. (2015) Sample code in Waterman et al. = code given to sample when truncated in Figures and Tables

Segment depth (mm) = depth of core cut and analysed

ANSTO radiocarbon identifier = code given to individual segments from cut core by ANSTO for analysis

PMC = Percent Modern Carbon. Processed samples are converted to pure graphite and carbon-14 measured using the STAR Accelerator Mass Spectrometer at ANSTO. Results can be compared to atmospheric carbon-14 to obtain age (CE).

PMC 1σ = carbon-14 is measured at very high accuracy using AMS. This is the 1 sigma error in Percent Modern Carbon.

Mean year and 1σ error (CE) = final segment calendar ages and 1 sigma errors for each moss core segment were modelled and calibrated (Common Era; Gregorian Year) against a constructed atmospheric radiocarbon curve using Bayesian analysis via OxCal version 4.2 programme (Bronk Ramsey 2009). See Waterman et al. (in prep) for more information.

δ13C-graphite and 1σ error (‰) = Carbon stable isotope signature of plant material converted to graphite (in per mil, ‰). Data are provided for δ13C where there was enough graphite remaining after radiocarbon analysis for replication. Those with insufficient sample are marked as n/a.

Δ13C and 1σ error (‰) = To separate changes in plant δ13C due to water environment from changes to source δ13C, stable carbon isotope values in each core section were calculated in relation according to (Farquhar, Ehleringer, and Hubick 1989b) as in Waterman et al. (in prep).

Funding and logistics support to collect these data were provided by Australian Research Council grants (DP110101714, DP180100113, DP200100223) ARC SRIEAS SR200100005 Securing Antarctica’s Environmental Future (SAEF) Australian Antarctic Science projects 2542, 3042, 3129, 4046 (Sharon Robinson), 4516 (Melinda Waterman), and 4613 (SAEF) Australian Nuclear Science and Technology Organisation (ANSTO) portal research grant (AP10732) Australian Institute of Nuclear Science and Engineering (AINSE) grants (05142P and 06155), and postgraduate award (ALNSTU2110, Waterman) University of Wollongong Advancement Grant 2019 (Melinda Waterman) FONDECYT 1120895 and FONDECYT 1140189 (Angelica Casanova-Katny) INACH RT14-17 (Gustavo Zúñiga) Antarctica New Zealand K500-A (Barbara Bollard) National Institute for Polar Research Japan (Satoshi Imura and Megumu Tsujimoto)

Lineage

Progress Code: completed